The present invention relates to a semiconductor control device, and more particularly relates to a power electronic unit that has a semiconductor module with a semiconductor element mounted on a cooling member and controls the supply of driving electricity to an electric motor.
In recent years, electric vehicles provided with an electric motor as its driving power source are becoming popular. Electric vehicles are provided with a semiconductor control device such as a PEU (Power Electronic Unit) that converts direct-current power supplied from a battery into alternating-current power and controls the supply of the power to the electric motor, and also according to need, performs a control such that alternating-current power generated by a regenerative mechanism is converted into direct-current power and the power is accumulated in a battery such at a time of braking, for example.
The power electronic unit is provided with a power module that converts direct-current power supplied from the battery into alternating-current power, and also according to need, converts the alternating-current power generated by the regenerative mechanism into direct-current power. Because such power modules are often used in plural, while positioning a plurality of power modules relatively close to each other, an electric wire electrically connecting the plurality of power modules with each other, and an electric wire electrically connecting the plurality of power modules with other constituent members and external devices, are routed near the power modules. Furthermore, the power modules convert power by combining a plurality of switching elements, and thus, they are often provided with a plurality of circuit boards that either operate or control the operations of the plurality of switching elements. Further, in the power modules, because a relatively high electric current is used, power semiconductor elements such as a Power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor) are often incorporated as a switching element. Because the operations of such power semiconductor elements are accompanied by the generation of a large amount of heat, heat sinks are mounted on power modules in order to secure a radiation route.
Japanese Patent Application Laid-open No. 2009-159704 relates to a power drive unit, and discloses a configuration provided with a heat sink, and a plurality of power modules arranged in a staggered shape on the heat sink. In such a power drive unit, when controlling the supply of three-phase alternating-current power to the electric motor, a total of six power modules are incorporated, that is, three power modules as high-side switching elements to be connected to a plus terminal of a battery, and three power modules as low-side switching elements to be connected to a minus terminal of the battery.
Japanese Patent Application Laid-open No. 2000-92888 relates to a motor control device, and discloses a configuration where a main printed circuit board that controls a motor applied voltage (an electric current) is connected, via a conversion wiring board that converts terminal arrangements and terminal positions, to a power module having a plurality of power-system elements incorporated therein, while the main printed circuit board is attached through a spacer to a radiator on which the power modules are attached.